About the author:

1.CCCC⁃SHEC Forth Engineering Co., Ltd., Luoyang, Henan 471000, China;2. CCCC Second Harbor Engineering Construction Technology Co., Ltd., Wuhan, Hubei 430050, China

Abstract:

As an important part of urban rail transit construction, shafts usually face special geologicalconditions and complex environments during construction, and the risk is high. Based on the shaft projectof the 13th bid section of the second phase of the civil engineering project of Chongqing Rail Transit Line15, the excavation process of the shaft is simulated by the finite element software MIDAS GTS NX, andthe stability of the supporting structure and surrounding rock of the shaft after excavation is analyzed, andthe construction of the shaft in the hard rock stratum under the limited space is summarized. The resultsindicate that with the excavation, the stress of the lower supporting structure decreases continuously, thevertical displacement of the surrounding rock decreases continuously along the shaft wall, and themaximum stress of the surrounding rock appears at the middle position of the bottom of the shaft withoutexcavation. Aiming at the excavation problem of a small cross⁃section shaft in hard rock stratum underlimited space, the method of rotary drilling to guide holes and the reversed shaft wall method is selectedto ensure the construction efficiency and safety.